比一比
10 (____) 19 7(____)17 13 (____) 3 18 (____) 18-5
13-6 (____) 6 14-5 (____) 15-4 15-4 (____) 10 12-8 (____) 11-5
锂电池能量密度高、绿色环保.现用充电宝为一手机锂电池(图甲)充电,等效电路如图乙所示,充电宝的输出电压为U,输出电流为I,该锂电池的内阻为r,则( )
下列各项中,有语病的一项是( )
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